WO2018008486A1

WO2018008486A1 - Centrifugal separator and centrifugal separation method

Info

Publication number: WO2018008486A1
Application number: PCT/JP2017/023712
Authority: WO
Inventors: 新平栗田; 満彦新田; 阿部　研; 知則渡會; 康史大友; 伸一郎名取
Original assignee: 月島機械株式会社
Priority date: 2016-07-05
Filing date: 2017-06-28
Publication date: 2018-01-11
Also published as: TWI702985B; EP3482830A1; CN109070099A; EP3482830A4; CN109070099B; KR102325794B1; JP2018001117A; TW201805068A; JP6578254B2; KR20190026644A

Abstract

A centrifugal separator equipped with: a cylindrical basket (2) which rotates around an axis (O); an extrusion plate (7) which is housed in the basket (2) and capable of integrally rotating with the basket, is capable of relative movement in the axial (O) direction, and extrudes to the opening end (2b) side thereof a cake which has been filtered by a filtration screen (2a) from a substance to be treated that was supplied to the interior of the basket (2); an advancing/withdrawing drive unit (11) for moving the extrusion plate (7) or the basket (2) relative to the other by advancing and withdrawing the plate or basket in the axial (O) direction; and a measurement unit for measuring the extrusion load caused by extruding the cake using the advancing/withdrawing drive unit (11). Control of the relative movement speed between the extrusion plate (7) and the basket (2) and/or the advancing/withdrawing stroke of the extrusion plate (7) or the basket (2) is performed on the basis of the extrusion load measured by the measurement unit.

Description

Centrifuge and centrifuge method

In the present invention, a processed product supplied in a basket rotated around an axis is filtered by a filter screen provided in a body portion of the basket, and a cake filtered from the processed product is accommodated in the basket. The present invention relates to an extrusion-type centrifuge device and a centrifuge method for discharging from an open end of a basket by an extrusion plate that can rotate integrally and move relative to the basket in the axial direction.
This application claims priority based on Japanese Patent Application No. 2016-133666 for which it applied to Japan on July 5, 2016, and uses the content here.

As such an extrusion-type centrifuge, for example, Patent Document 1 discloses an outer basket that is rotated around an axis, and is coaxially disposed in the outer basket and rotated integrally with the outer basket. A two-stage basket type centrifuge having an inner basket that is advanced and retracted in a direction is disclosed. In this two-stage basket type centrifuge, a processed product to be filtered by centrifugation is supported by the outer basket and is disposed in the inner basket so as to face the opening of the processed product supply pipe; It supplies between this extrusion board and the annular plate-like distributor arrange | positioned so that the opening part of a processed material supply pipe may be surrounded.

In such a centrifugal separator, the processed material supplied between the extrusion plate and the distributor from the opening of the supply pipe is deposited on the inner peripheral surface of the filtration screen provided on the barrel of the inner basket by centrifugal force. While being filtered, a cake is formed. Further, the cake accumulates also in the axial direction of the inner basket by the advance of the inner basket toward the opening end side of the outer basket. Next, the cake of the processed product is pushed out by the extrusion plate by the retraction of the inner basket with respect to the outer basket and discharged to the inner peripheral surface of the outer basket. In addition, the cake of the processed product thus discharged onto the inner peripheral surface of the outer basket is further filtered by the filtration screen of the outer basket, pushed out by the advance of the inner basket, and discharged from the open end of the outer basket.

Japanese Laid-Open Patent Publication No. 2014-091093

In such a centrifugal separator, the relative movement of the basket and the extrusion plate in the axial direction (in the centrifugal separator described in Patent Document 1, the advance and retreat of the inner basket with respect to the extrusion plate) is generally a hydraulic pressure by a hydraulic piston. By driving. For this reason, the stroke of movement during forward movement and the stroke of movement during backward movement, and the movement speed during forward movement and the movement speed during backward movement are made equal to each other.

In such a centrifugal separator, the load on the centrifugal separator due to the solid content of the processed product to be subjected to solid-liquid separation and dehydration is not always constant, the amount of processed product supplied and the solid content concentration in the processed product The fluctuation of the load causes increase / decrease in load due to solid content. As the amount of solids increases and the load increases due to an increase in the supply amount and solid concentration of the processed material, the thickness of the cake filtered from the processed material by the filter screen increases and forms on the inner peripheral surface of the filter screen. The thickness of the cake layer thus formed becomes uneven, and abnormal vibration may occur in the basket that rotates at high speed.

Conversely, when the relative movement speed and movement stroke between the basket and the extrusion plate are set large in advance with respect to the load due to such solid content, the thickness of the cake formed on the inner peripheral surface of the filtration screen Becomes thinner, the amount of cake held in the basket is reduced, and the residence time of the processed product in the basket is shortened. Factors affecting the dewatering performance of the centrifugal separator are mainly the centrifugal force due to the rotation of the basket and the residence time in the basket. Therefore, if the operation is performed in a state where the residence time is short, the dewatering performance of the centrifugal separator is excessive with respect to the load due to the solid content, and the dewatering performance of the centrifugal separator is not sufficiently exhibited.

The present invention is made under such a background, and responds to increase / decrease in the load accompanying fluctuations in the supply amount of the processed material and the solid content concentration, and the occurrence of abnormal vibration is maintained by maintaining the cake thickness uniform. In addition, an object of the present invention is to provide a centrifuge device and a centrifuge method that can exhibit dewatering performance without excess or deficiency.

A first aspect of the centrifugal separator according to the present invention includes a cylindrical basket provided with a filtration screen in a body portion and rotated around an axis, and accommodated in the basket and rotatable integrally with the basket. An extrusion plate that is provided so as to be relatively movable in the axial direction and that extrudes the cake filtered by the filtration screen from the processed product supplied in the basket to the open end side of the basket, and one of the extrusion plate and the basket An advancing / retreating drive unit that moves forward and backward in the axial direction relative to the other, and an advancing / retreating drive when the cake is pushed out to the opening end side of the basket by one of the pushing plate and the basket by the advancing / retreating drive unit A push-out plate and a basket by an advancing / retreating drive unit based on the push-out load measured by the measuring unit. And the relative moving velocity, at least one of which is controlled with the stroke of the reciprocating against one other of the extrusion plate and basket.

In the first aspect of the centrifugal separation method of the present invention, a processed product is supplied into a cylindrical basket that is provided with a filtration screen in a body portion and is rotated about an axis, and is filtered from the processed product by the filtration screen. A centrifugal separation method for extruding and discharging a cake to an open end side of a basket by an extrusion plate that is accommodated in a basket and can be rotated together and moved relative to the basket in an axial direction. The extruding plate and the basket are moved in the axial direction relative to the other by the advancing / retreating driving unit and moved relative to each other, and the cake is moved by the advancing / retreating of the extruding plate and the basket by the advancing / retreating driving unit. The extrusion load at the advancing / retreating drive unit when pushed out to the open end side of the basket is measured by the measurement unit, and the extrusion load measured by this measurement unit Based, the relative movement speed of the pushing plate and the basket by the advancing drive unit, controls at least one of the stroke of the reciprocating against one other of the extrusion plate and basket.

In the first aspect of such a centrifugal separator and the first aspect of the centrifugal method, for example, as in the centrifugal separator described in Patent Document 1, the extruded plate is at a fixed position in the axial direction, and the basket is When it is possible to move forward and backward in the axial direction, at least one of the moving speed and the forward and backward stroke of the basket with respect to the push-out plate is controlled. Conversely, when the basket is at a fixed position in the axial direction and the pusher plate is movable back and forth in the axial direction, the movement speed of the pusher plate by the advancing / retreating drive unit and the advance / retreat stroke At least one is controlled.

Therefore, in any case, the above-described extrusion load tends to increase, that is, the solid load increases due to an increase in the supply amount of the processed material or the solid content concentration in the processed material, and the cake becomes thicker. When there is a characteristic, control is performed so that at least one of the relative movement speed and the stroke increases. Thereby, the supply amount of the processed product per unit length in the axial direction of the filtration screen can be reduced, and the thickness of the cake can be made uniform. For this reason, it is possible to prevent abnormal vibrations and the like from being formed on the filtration screen of the basket that rotates at high speed, and to perform stable filtration.

On the other hand, when the load due to the solid content decreases due to the decrease in the supply amount of the processed material or the solid content concentration in the processed material, and the extrusion load tends to decrease, the relative movement speed and the stroke Control is performed so that at least one of them decreases. Thereby, the processed material supply amount per unit length in the axial direction of the filtration screen can be increased. For this reason, it is possible to prevent the formation of a cake having a non-uniform thickness, and to ensure a long residence time of the processed material in the basket so that the dewatering performance of the centrifugal separator can be fully demonstrated and balanced. It becomes possible to promote efficient filtration.

Of these, in order to control the relative movement speed of the extrusion plate and the basket, for example, even when one of the basket and the extrusion plate is moved forward and backward with respect to the other by hydraulic driving by a conventional hydraulic piston, the forward movement and the backward movement are performed. It is possible to control by making a difference in the flow rate of the hydraulic oil, setting a speed controller, or providing a difference in the discharge speed of the hydraulic oil by bypassing the cylinder discharge side flow channel. However, in this case, the hydraulic pressure becomes unstable when switching between advance and retreat, and it may be difficult to control to a predetermined relative movement speed. Further, it is almost impossible to control the advance / retreat stroke between the push plate and the basket by a hydraulic drive by a general hydraulic piston.

Therefore, as described above, in order to stably control at least one of the relative movement speed of the extrusion plate and the basket and the advance / retreat stroke with respect to the other one of the extrusion plate and the basket, the advance / retreat driving unit includes the advance / retreat drive unit. It is desirable that the motor is driven by an electric motor that has high responsiveness in switching and moving speed control, and can switch forward and backward with an arbitrary stroke.

As an advance / retreat drive unit driven by such an electric motor, for example, the rotation of an electric motor (servo motor) transmitted to a screw shaft such as a ball screw is screwed into a screw shaft with a nut coaxially attached to a piston rod. It is possible to use a so-called electric cylinder that converts the linear motion of the piston rod. In addition, it is possible to use a linear cylinder in which the piston rod is linearly moved directly by an electric linear motor. Furthermore, there are so-called fastener-type actuators, etc., in which two or more chains are engaged with each other and fed forward by an electric motor in a columnar shape, and are linearly moved by pulling back and retracting while releasing the meshing of the chains. .

In particular, when the advancing / retreating drive unit is driven by an electric motor, the pushing load can be measured from the current value of the electric motor in the advancing / retreating drive unit as the measurement unit. Therefore, since the load of the solid substance actually acting on the advance / retreat driving unit can be measured in real time, more reliable and stable control can be achieved. As such a measurement unit, for example, a load cell provided in the advance / retreat drive unit can be used not only when the advance / retreat drive unit is an electric motor but also by hydraulic drive.

According to the present invention, the cake thickness is kept uniform to prevent the occurrence of abnormal vibrations regardless of the increase or decrease of the load accompanying fluctuations in the supply amount of the processed material or the solid content concentration, and the dehydration performance is not excessive and insufficient. It is possible to promote stable and efficient filtration.

It is sectional drawing which shows the outline of 1st Embodiment of the centrifuge of this invention. In the embodiment shown in FIG. 1, it is an expanded sectional view of the basket periphery showing a state in which the inner basket is retracted with respect to the extrusion plate. In the embodiment shown in FIG. 1, it is an expanded sectional view of the basket periphery which shows the state which the inner basket advanced with respect to the extrusion plate. In 2nd Embodiment of the centrifuge of this invention, it is an expanded sectional view of a basket periphery which shows the state which the extrusion board advanced with respect to the basket. FIG. 5 is an enlarged cross-sectional view around the basket showing a state in which the extruded plate is retracted with respect to the basket in the embodiment shown in FIG. 4.

1 to 3 show a first embodiment of a centrifuge of the present invention. The present invention is a two-stage basket type centrifuge equipped with an outer basket and an inner basket as described in Patent Document 1. FIG. This is an example applied to a separation device. That is, the centrifugal separator in the present embodiment is accommodated coaxially in a cylindrical outer basket 1 centering on a horizontal axis O having an outer filtration screen 1a attached to the body, and the outer basket 1. A cylindrical inner basket 2 having an inner filtration screen 2a attached to the body portion is provided. In the first embodiment, the inner basket 2 is a basket in the present invention. As the outer filtration screen 1a and the inner filtration screen 2a, for example, a cylindrical wire screen or a plate screen is used.

Circular open ends 1b and 2b are provided at one end (the right end in the direction of the axis O in FIGS. 1 to 3) of the cylindrical outer basket 1 and the inner basket 2 in the direction of the axis O, and the other end (FIGS. 1 to 3). (The left end in the direction of the axis O) is a bottomed cylindrical shape attached to and held by the disc-

like holding plates

1c and 2c. The length of the inner basket 2 in the axis O direction is shorter than the length of the outer basket 1 in the axis O direction. The inner basket 2 is accommodated in the casing 3 and rotated integrally with the outer basket 1 around the axis O. The outer diameter of the opening end 2b of the inner basket 2 is large enough to be slidably contacted with the inner peripheral surface of the outer filtration screen 1a of the outer basket 1 by providing, for example, another annular annular plate (not shown) at the opening end 2b. It is assumed.

The holding plate 1c of the outer basket 1 is rotatably supported by a bearing 4 and attached to one end of a hollow main shaft 5 inserted into the casing 3 along the axis O. The outer basket 1 rotates around the axis O when the rotational force of a motor or the like is transmitted to a pulley (not shown) and the main shaft 5 rotates. An extrusion shaft 6 is inserted into the main shaft 5 via a key (not shown) so as to be integrally rotatable and capable of moving back and forth in the direction of the axis O. One end of the extrusion shaft 6 slidably passes through the holding plate 1c of the outer basket 1 and is attached to the holding plate 2c of the inner basket 2, so that the inner basket 2 can also rotate integrally with the outer basket 1. In addition, the other basket in the outer basket 1 can be advanced and retracted in the direction of the axis O.

Further, a plurality of support shafts 1d are provided on the holding plate 1c of the outer basket 1 so as to extend to the one end side in parallel to the axis O at a position spaced apart from the axis O toward the outer periphery in the circumferential direction. It is attached. These support shafts 1 d project through the holding plate 2 c so as to be slidable and protrude into the inner basket 2. At one end of these support shafts 1d, a disc-shaped extruded plate 7 having an outer diameter that can slide on the inner peripheral surface of the inner filtration screen 2a is attached. Therefore, the extrusion plate 7 can rotate integrally around the axis O coaxially with the outer basket 1 and the inner basket 2 and can move relative to the inner basket 2 in the direction of the axis O.

In addition, an annular plate-like dispersion plate (distributor) 8 having an opening in the center is integrally supported on one end side of the extrusion plate 7 with a space from the extrusion plate 7. Further, a supply pipe 9 for the processed material is attached to the casing 3 and inserted therethrough. The supply pipe 9 passes through the opening ends 1 b and 2 b of the outer basket 1 and the inner basket 2 and is inserted into the opening of the dispersion plate 8, and the supply port of the supply pipe 9 is interposed between the extrusion plate 7 and the dispersion plate 8. It is open.

Further, a substantially U-shaped cake receiving ring 3a whose cross section along the axis O opens to the inner peripheral side is supported by the casing 3 on the outer periphery of the open end 1b of the outer basket 1 so as to surround the open end 1b. It is arranged. The cake receiving ring 3a is provided with a cake chute (not shown). After the cake discharged from the open end 1b of the outer basket 1 is received by the cake receiving ring 3a, the cake chute is inserted into the casing via the cake chute. 3 is discharged from a discharge port 3b provided below 3.

On the other hand, the other end of the extrusion shaft 6 protrudes from the other end of the main shaft 5, while allowing the rotation of the extrusion shaft 6 to the other end portion of the protruding extrusion shaft 6 via the bearing box 10, An advancing / retreating drive unit 11 is connected to move the pushing shaft 6 in the direction of the axis O together with the inner basket 2. The bearing box 10 is configured so as not to rotate with respect to the extrusion shaft 6 that rotates integrally with the main shaft 5 while rotatably supporting the other end portion of the extrusion shaft 6 by a bearing or the like (not shown). It is attached to the extrusion shaft 6 so as to be able to advance and retract.

Furthermore, the advancing / retreating drive unit 11 in this embodiment is driven by an electric motor, and in particular, the rotation of the electric motor (servo motor) 11a is arranged in the cylinder box 11b so as to extend in the direction of the axis O, such as a ball screw (not shown). Transmit to the screw shaft. A nut that is coaxially attached to a piston rod (not shown) is screwed onto the screw shaft, and the advance / retreat drive unit 11 converts the rotation of the electric motor 11a into a linear motion of the piston rod via the screw shaft and the nut. To do. Such an advancing / retreating drive unit 11 is a so-called electric cylinder, a servo cylinder, or an electric actuator.

In one embodiment of the centrifugal separation method of the present invention using the centrifugal separator configured as described above, the processed product in which the solid liquid is turbid from the supply pipe 9 while rotating the outer basket 1 and the inner basket 2 together. (Slurry) is supplied. The supplied processed product hits the extrusion plate 7 and is dispersed from the space between the dispersion plate 8 and the outer peripheral side by centrifugal force, and adheres to the inner peripheral surface of the inner filtration screen 2 a of the inner basket 2. Therefore, when the inner basket 2 is advanced from the state in which the inner basket 2 is retracted with respect to the extrusion plate 7 as shown in FIG. The processed material is filtered by centrifugal force while continuously depositing on the inner peripheral surface in the direction of the axis O, thereby forming a cake of the processed material.

Next, when the inner basket 2 thus advanced reaches the forward stroke end and turns backward as shown in FIG. 3, the cake of the processed material deposited on the inner peripheral surface of the inner filtration screen 2a is retracted. The push-out plate 7 that moves forward relative to the basket 2 is sequentially pushed toward one end of the inner basket 2. The cake of cake (cake) deposited on the one end side is discharged from the open end 2b to the inner peripheral surface of the outer filtration screen 1a of the outer basket 1, and is further deposited by centrifugal force while continuously depositing in the direction of the axis O. It will be filtered. When the supply amount and the solid content concentration of the processed product to be supplied are stable, the pushing load by the advancing / retreating drive unit 11 when the inner basket 2 moves forward and the cake of the processed product is pushed out is also within a predetermined range. And stable.

Subsequently, the cake of the processed material deposited and filtered on the inner peripheral surface of the outer filtration screen 1a in this way is moved to the open end 2b of the inner basket 2 by the next advance of the inner basket 2 reaching the retreat stroke end, or It is sequentially pushed to one end side by the other push plate (not shown) provided at the open end 2b. Subsequently, the cake of the processed material accumulated on one end side is discharged from the opening end 1b of the outer basket 1 to the cake receiving ring 3a, and further discharged from the discharge port 3b of the casing 3 through the cake chute (not shown) as described above. Is done.

In the centrifugal separator having the above-described configuration, the processed material is transferred by the advance / retreat of the push-out plate 7 by the advance / retreat drive unit 11 and one of the inner baskets 2 (the inner basket 2 in the present embodiment). A measuring unit 15 that measures the extrusion load in the advance / retreat drive unit 11 when the cake is pushed out toward the open end 2b of the inner basket 2 is provided. In the centrifugal separator and the centrifugal method using the centrifugal separator, based on the extrusion load measured by the measuring unit 15, the relative movement speed of the extruded plate 7 and the inner basket 2 by the advance / retreat driving unit 11, the extruded plate 7 And at least one of the advancing and retreating strokes with respect to the other of the inner baskets 2 is controlled.

That is, in the centrifugal separator and the centrifugal method of the present embodiment, the supply amount of the processed material and the solid content concentration vary from the stable state as described above, and the extrusion load tends to increase from the predetermined range. In the case of the above, at least one of the relative movement speed and the stroke is controlled to increase. On the contrary, when the pushing load tends to decrease from the predetermined range, control is performed so that at least one of the relative moving speed and the stroke is decreased.

In this embodiment, the measurement unit 15 measures the extrusion load by measuring the current value of the electric motor 11a in the advance / retreat drive unit 11. The above-described control is performed by a computer including a well-known constituent member such as a CPU and a memory for controlling the electric motor 11a so as to control the electric motor 11a based on the pushing load measured by the measuring unit 15. By inputting a program in the control unit in advance, it can be performed automatically and easily.

Specifically, in the present embodiment, the extrusion plate 7 is attached to the main shaft 5 via the support shaft 1d and the holding plate 1c of the outer basket 1 and fixed in the direction of the axis O, while the inner basket 2 is It is advanced and retracted in the direction of the axis O through the extrusion shaft 6. Therefore, when controlling to increase the relative movement speed when the extrusion load increases, the following control is performed. That is, as shown in FIG. 2, when the inner basket 2 is retracted to the other end side in the direction of the axis O and the distance D between the opening end 2b and the extrusion plate 7 in the direction of the axis O is small, the inner basket 2 is moved to the axis O. As shown in FIG. 3, the opening end 2b of the inner basket 2 is separated from the extrusion plate 7 so as to increase the relative movement speed in the direction in which the interval D increases as shown in FIG. Is done. On the contrary, the relative movement speed is controlled so as to increase from the state in which the distance D is large to the direction in which the distance D decreases.

On the other hand, when the extrusion load decreases from a predetermined range, the relative movement speed in the direction in which the interval D shown in FIG. 3 increases from the state where the interval D shown in FIG. 2 is small, and the interval shown in FIG. Control is performed so that the relative movement speed in the direction in which the distance D shown in FIG.

On the other hand, a case will be described in which the advance / retreat stroke of one of the push plate 7 and the inner basket 2 (the inner basket 2 in this embodiment) and the other (the push plate 7 in this embodiment) is controlled. For example, the advance / retreat stroke of the inner basket 2 when the pushing load is in the predetermined range is set in advance so as to be smaller than the maximum stroke of the piston rod by the advance / retreat drive unit 11. When the pushing load measured by the measuring unit 15 increases beyond the predetermined range, the inner basket 2 is moved forward and backward with a stroke larger than the stroke of the inner basket 2 when it is in the predetermined range. On the contrary, when the pushing load becomes smaller than the predetermined range, the inner basket 2 is moved back and forth with a stroke smaller than the stroke of the inner basket 2 when it is in the predetermined range.

In the centrifugal separator and the centrifugal method configured as described above, when the supply amount of the processed material and the solid content concentration increase and the extrusion load exceeds the predetermined range, the extrusion plate 7 by the advance / retreat driving unit 11 is used. When the relative movement speed of the inner basket 2 is increased, the following effects can be obtained. That is, after the interval D shown in FIG. 2 is small and the interval D shown in FIG. 3 is large, the processed material deposited on the inner peripheral surface of the inner filtration screen 2a is extruded by the extrusion plate 7. The amount of solid content contained in the processed product supplied to the filtration screen 2a is reduced per unit length in the axis O direction. Therefore, when the processed product is filtered by centrifugal separation, the thickness of the cake remaining on the inner peripheral surface of the inner filtration screen 2a is determined when the supply amount and the solid content concentration are stable and the extrusion load is within a predetermined range. The cake thickness can be uniform.

Further, the inner basket 2 moves backward from the pushing plate 7 toward the other end side in the axis O direction from the state where the distance D shown in FIG. 3 is large to the state where the distance D shown in FIG. The following effects are obtained when the processed material on the opening end 2b side is pushed out. That is, the processed product supplied from between the extrusion plate 7 and the dispersion plate 8 is placed on the processing product deposited on one end side of the extrusion plate 7 (inner circumference). At this time, since the relative moving speed of the inner basket 2 with respect to the extruded plate 7 is large, the solid content in the processed product added per unit length in the direction of the axis O decreases, and the cake thickness becomes too thick. Can be prevented.

On the other hand, when the supply amount of the processed material and the solid content concentration are stable and the extrusion load exceeds the predetermined range, the stroke of the advance / retreat of the inner basket 2 relative to the extrusion plate 7 is increased. The following effects can be obtained. That is, even when the interval D is increased or decreased, the processed material having a large supply amount or solid content concentration is dispersed in a wider range in the direction of the axis O and is supplied to the inner peripheral surface of the inner filtration screen 2a. , Can prevent the cake thickness from becoming thick. Further, when the forward / backward stroke of the inner basket 2 is reduced when the extrusion load becomes smaller than a predetermined range, the processed product with a small supply amount and solid content concentration is within a relatively small range of the inner filtration screen 2a. Since it is supplied to the inner peripheral surface, it is possible to prevent the cake from becoming too thin.

As described above, according to the centrifugal separator and the centrifugal separation method having the above-described configuration, the supply amount of the processed material and the solid content concentration in the processed material increase to increase the load due to the solid content, and the extrusion load increases accordingly. In this case, by increasing at least one of the relative movement speed of the inner basket 2 with respect to the extrusion plate 7 and the advance / retreat stroke, the cake thickness can be prevented from becoming too thick and the cake thickness can be made uniform. On the other hand, when the supply amount of the processed material or the solid content concentration decreases and the extrusion load becomes small, the cake thickness becomes too thin by reducing at least one of the relative movement speed and the stroke. The cake thickness can be made uniform.

For this reason, even if the supply amount of the processed material and the solid content concentration fluctuate, a portion where the thickness of the cake is not uniform is formed on the inner peripheral surface of the inner filtration screen 2a of the inner basket 2 rotating at high speed. Can be prevented. Therefore, it is possible to prevent the possibility of abnormal vibration occurring in the inner basket 2 due to such non-uniform cake thickness, and to promote stable filtration of the processed product by centrifugation.
In particular, even when the supply amount of the processed material and the solid content concentration are decreased, the retention time of the processed material in the inner basket 2 can be secured long by reducing the relative movement speed and the advance / retreat stroke. Therefore, it is possible to achieve efficient filtration by exhibiting the performance of the centrifugal separator without excess or deficiency.

Furthermore, in the centrifugal separator of the present embodiment, as the advance / retreat drive unit 11 that advances and retracts the inner basket 2 in the direction of the axis O with respect to the extrusion plate 7, the rotation of the electric motor 11a is pushed out from the piston rod via a screw shaft and a nut. An electric cylinder that converts the linear motion of the shaft 6 is employed. The advancing / retreating drive unit 11 using such an electric motor 11a has higher responsiveness at the time of switching between advancing and retreating, and increases / decreases the relative movement speed and the advancing / retreating stroke as described above. Even in this case, it is possible to easily and quickly respond by controlling the rotation of the electric motor 11a. Therefore, it is particularly effective when performing control such as the centrifuge and the centrifuge method having the above-described configuration.

Note that the forward / backward drive unit 11 by such an electric motor 11a is not limited to an electric cylinder that converts the rotation of the electric motor 11a into a linear motion of a piston rod by a screw shaft and a nut as in the above embodiment. For example, a linear cylinder that linearly moves the piston rod and the extrusion shaft 6 directly by an electric linear motor may be used. Two or more chains connected to the extrusion shaft 6 are meshed with each other and fed forward by an electric motor to move forward, and are pulled back and retracted while unlocking the chain to make a linear motion. An actuator or the like may be used.

In addition to adopting the centrifugal separator using the electric motor 11a as the advance / retreat drive unit 11, in the present embodiment, when measuring the extrusion load when extruding the cake of the processed product, the electric drive in the advance / retreat drive unit 11 The measuring part 15 measures the current value of the motor 11a to measure the extrusion load. Therefore, the extrusion load when the processed cake is being extruded can be measured in real time, and the measured result can be quickly reflected in the control of the advance / retreat drive unit 11. Therefore, more reliable and stable control. Can be encouraged. When at least one of the extrusion load thus measured and the relative movement speed and stroke controlled based on this extrusion load becomes a preset upper limit value or lower limit value, an alarm is given as an abnormality. It may be controlled to start or stop the centrifuge.

Next, FIG. 4 and FIG. 5 show a second embodiment of the centrifuge of the present invention. Portions common to the centrifuge of the first embodiment are assigned the same reference numerals and description thereof is omitted.
In the centrifuge of the second embodiment shown in FIGS. 4 and 5, the other end portion in the direction of the axis O (not shown) is the same as that of the centrifuge of the first embodiment, so that the illustration is omitted.

In the first embodiment, the inner basket 2 is accommodated in the outer basket 1 so as to be integrally rotatable, and the inner basket 2 is attached to the extrusion shaft 6 and is advanced and retracted in the direction of the axis O. The extruding plate 7 supported thereby is held at a fixed position in the direction of the axis O, so that the extruding plate 7 can move relative to the basket (inner basket 2) in the direction of the axis O. In the second embodiment, a single basket 21 having a filtering screen 21a at the body and having an open end 21b at one end in the direction of the axis O is attached to one end of the main shaft 5 via a holding plate 21c. . A basket 21 is held at a fixed position in the direction of the axis O, and an outer diameter push plate 22 slidably contacting the inner peripheral surface of the filter screen 21a is coaxially connected to one end of the push shaft 6 inserted through the holding plate 21c. It moves forward and backward in the direction of the axis O. Thereby, the extrusion plate 22 is movable relative to the basket 21 in the direction of the axis O.

Therefore, in the second embodiment, the basket 21 and the opening end 21b of the basket 21 are movable at a fixed position in the direction of the axis O, and the pusher plate 22 is moved back and forth in the direction of the axis O. Therefore, the direction in which the distance D in the direction of the axis O between the pushing plate 22 and the opening end 21b of the basket 21 increases is shown in FIG. 5 from the state in which the pushing plate 22 advances in the basket 21 as shown in FIG. The direction when retreating. Further, the direction in which the distance D becomes smaller is the direction when the extruded plate 22 moves forward as shown in FIG. 4 from the state where the extruded plate 22 moves backward as shown in FIG. Therefore, when the extrusion plate 22 moves forward, the cake of the processed material accumulated on the inner peripheral surface of the filtration screen 21a of the basket 21 is discharged from the opening end 21b side of the basket 21 to the cake receiving ring 3a.

Also in the second embodiment, based on the pushing load by the electric motor 11a measured by the measuring unit 15 provided in the advance / retreat drive unit 11, the relative movement speed of the push plate 22 and the basket 21 by the advance / retreat drive unit 11, and At least one of the forward and backward strokes of the extrusion plate 22 with respect to the basket 21 is controlled. Specifically, the extrusion load is measured based on the current value of the electric motor 11a, and the extrusion load tends to increase from a state where the processed material supply amount and solid content concentration are stable and the extrusion load is stable. When it is, the control is performed so that at least one of the relative movement speed and the stroke increases. Conversely, when the extrusion load tends to decrease, control is performed so that at least one of the relative movement speed and the stroke decreases.

Also in the second embodiment, when the supply amount of the processed material or the solid content concentration in the processed material fluctuates, it is possible to control the filtration by controlling at least one of the relative movement speed of the extrusion plate 22 with respect to the basket 21 and the forward / backward stroke. The thickness of the cake formed on the inner peripheral surface of the screen 21a can be maintained uniformly. For this reason, it is possible to prevent abnormal vibration from occurring in the basket 21 and promote stable filtration of the processed product by centrifugation. Further, when the amount of processed material supplied and the solid content concentration decrease, the residence time of the processed material in the basket 21 can be ensured by reducing the relative movement speed and the advance / retreat stroke of the extrusion plate 22. Therefore, it is possible to achieve efficient filtration by exhibiting the performance of the centrifugal separator without excess or deficiency.

Also in this embodiment, the advancing / retreating drive unit 11 by the electric motor 11a is used. By controlling the electric motor 11a, the relative movement speed and the advancing / retreating stroke can be controlled easily and quickly. Further, since the extrusion load can be measured in real time based on the current value of the electric motor 11a, it is possible to quickly cope with a sudden change in the amount of processed material supplied and the solid content concentration.

In the second embodiment and the first embodiment, in addition to adopting the advance / retreat drive unit 11 using the electric motor 11a, the current value of the electric motor 11a is measured by the measuring unit 15 to measure the extrusion load. is doing. Not limited to this, for example, a load cell is disposed as a measuring unit 15 on the extrusion shaft 6 or the like, and the relative movement speed and advance / retreat of the

extrusion plates

7 and 22 and the

baskets

2 and 21 are determined based on the extrusion load measured by the load cell. It is also possible to control the stroke.

When measuring the extrusion load with a load cell, the present invention provides a centrifugal separation in which one of the basket and the extrusion plate is moved forward and backward with respect to the other by hydraulic drive by a conventional hydraulic piston, particularly when the relative movement speed is controlled. You may apply to an apparatus and the centrifugation method. For example, by making a difference in the flow diameter of the hydraulic oil at the time of forward movement and backward movement, installing a speed controller, or providing a difference in the hydraulic oil discharge speed by bypassing the cylinder discharge side flow path, It is possible to apply.

However, in such a forward / backward drive unit by hydraulic drive, the hydraulic pressure becomes unstable when the push-out

plates

7 and 22 and the

baskets

2 and 21 are switched back and forth, making it difficult to control to a predetermined relative movement speed. there is a possibility. In addition, since the hydraulic oil viscosity changes depending on the oil temperature, it is difficult to stabilize the hydraulic pressure, and cooling water is required to cool the hydraulic oil to control the oil temperature, and the hydraulic oil deteriorates over a long period of operation. Maintenance such as oil change due to oil and periodic oil filter replacement is also complicated. Furthermore, in the hydraulic drive by a general hydraulic piston, it is almost impossible to control the advance / retreat stroke of the push plate and the basket.

For this reason, in order to control at least one of the relative movement speed of the extrusion plate and the basket by the advance / retreat driving unit and the advance / retreat stroke with respect to the other of the extrusion plate and the basket, the first and second of the present invention are used. It is desirable to employ an advancing / retreating drive unit using an electric motor as in the embodiment. In the first embodiment, the present invention is applied to a centrifuge having a two-stage basket of an outer basket 1 and an inner basket 2, and a centrifuge having a single basket 21 and a centrifuge method in the second embodiment. Although the case where it applies is demonstrated, you may apply this invention to the centrifugation apparatus and centrifugation method which have a basket of three or more steps.

According to the centrifuge and the centrifuge method of the present invention, the cake thickness is kept uniform to prevent the occurrence of abnormal vibration regardless of the increase or decrease of the load accompanying the fluctuation of the supply amount of the processed material or the solid content concentration. In addition, dehydration performance can be exhibited without excess and deficiency, and stable and efficient filtration can be promoted.

DESCRIPTION OF SYMBOLS 1 Outer basket 1a Outer filtration screen 1b Open end of outer basket 1 2 Inner basket (basket)
2a Inner filtration screen 2b Open end of inner basket 2 3 Casing 5 Main shaft 6

Extrusion shaft

7, 22 Extrusion plate 8 Dispersion plate 9 Processed product supply pipe 10 Bearing box 11 Advance / retreat drive unit 11a Electric motor 11b Cylinder box 15 Measurement unit 21 Basket 21a Filtration screen 21b Open end of basket 21 O Axis of rotation of basket 21 (outer basket 1, inner basket 2) D In the direction of axis O between

extrusion plates

7, 22 and inner basket 2,

open ends

2b, 21b of basket 21 interval

Claims

A cylindrical basket provided with a filtration screen in the body and rotated around an axis,
The cake accommodated in the basket, rotatable integrally with the basket and movable relative to the basket in the axial direction, and filtered by the filtration screen from the processed material supplied in the basket. An extrusion plate extruded to the open end side of the basket;
An advancing / retreating drive unit for moving one of the extrusion plate and the basket in the axial direction relative to the other to move relatively;
A measuring unit that measures an extrusion load in the advancing / retreating driving unit when the cake is pushed out to the opening end side of the basket by one of the advancing plate and the basket by the advancing / retreating driving unit;
Based on the pushing load measured by the measuring unit, at least one of the relative movement speed of the pushing plate and the basket by the advance / retreat driving unit, and the advance / retreat stroke with respect to the other of the pushing plate and the basket. Centrifuge controlled.
2. The centrifugal separator according to claim 1, wherein at least one of the relative movement speed and the stroke is controlled to increase when the extrusion load tends to increase.
3. The centrifugal separator according to claim 1 or 2, wherein when the pushing load tends to decrease, control is performed so that at least one of the relative movement speed and the stroke decreases.
3. The centrifugal separator according to claim 1, wherein the advance / retreat drive unit is driven by an electric motor.
The centrifuge according to claim 4, wherein the measuring unit measures the push load from a current value of the electric motor in the advance / retreat driving unit.
The centrifuge according to any one of claims 1 to 4, wherein the measuring unit is a load cell provided in the advance / retreat driving unit.
A processed product is supplied into a cylindrical basket provided with a filter screen in the body and rotated about an axis, and cake filtered from the processed product by the filter screen is accommodated in the basket and integrated. A centrifugal separation method for extruding and discharging to the opening end side of the basket by an extrusion plate that is rotatable and movable relative to the basket in the axial direction,
One of the extrusion plate and the basket is moved forward and backward in the axial direction relative to the other by an advance / retreat drive unit,
Measuring the pushing load in the advance / retreat drive unit when the cake is pushed out to the opening end side of the basket by the advance / retreat of one of the push plate and the basket by the advance / retreat drive unit,
Based on the pushing load measured by the measuring unit, at least one of the relative movement speed of the pushing plate and the basket by the advance / retreat driving unit, and the advance / retreat stroke with respect to the other of the pushing plate and the basket. Centrifuge method to control.
The centrifugal separation method according to claim 7, wherein when the extrusion load tends to increase, control is performed so that at least one of the relative movement speed and the stroke increases.
The centrifugal separation method according to claim 7 or 8, wherein when the extrusion load tends to decrease, control is performed so that at least one of the relative movement speed and the stroke decreases.